The invention relates to a high density intelligence display such as a matrix type liquid crystal display panel with a so-called matrix electrode structure having crossing strip electrodes, and more particularly to a terminal connection structure of such a display panel.
In recent years, a substantial amount of effort has been devoted in the field of liquid crystal matrix displays to accomplish a high-density multiline display, aiming at an improvement in image quality. Liquid crystal displays with matrix shaped electrode structures are quite favorable to fulfill a power saving demand because of their capability of being excited with low power consumption.
For the matrix type liquid crystal display panel, the greater the number of the rows (scanning line number), the higher the density and accuracy of display. However, with an increase in the number of the rows, the length of time at which a signal is applied per column, i.e., duty factor, would be shortened and the problem arises that crosstalk takes place. In particular, liquid crystal display panels show dull threshold characteristics and slow response characteristics, resulting in difficulty in assuring a satisfactory contrast. There have been several attempts to overcome the problem:
(1) The development of liquid crystal material having more definite threshold properties;
(2) A matrix address scheme in the optimum condition with an extended operating margin (V=V.sub.on /V.sub.off); and
(3) The design of a new electrode layout with a higher resolution. For example, as shown in FIG. 1(a), column electrodes are divided into the upper half Y.sub.1, Y.sub.2, . . . Y.sub.n and the lower half Y.sub.1 ', Y.sub.2 ', . . . Y.sub.n ' while line electrodes X.sub.1, X.sub.2, . . . X.sub.m are operatively associated in common with the upper and lower halves. In an alternative way of FIG. 1(b ) two adjacent column electrodes Y.sub.j and Y.sub.j+1 are of a comb-teeth shape to mesh with each other within a respective one of the line electrodes X.sub.i.
Although the first two methods (1) and (2) do not need modifications in the liquid crystal cell structure, it is not possible to increase, remarkably, the number of actuable line electrodes. In contrast, the last method (3) can surely obtain an increased number of actuable or useful line electrodes, for example 2, 2.sup.2, etc., but will suffer from complexity of cell structure.
The two-layered matrix panel will now be described in greater detail.
As more clearly, shown in FIG. 2, the two-layered matrix type comprises, in general, a first transparent support 1, a second transparent support 2 and a third support 3 disposed in the named order. While the first support 1 carries column electrodes 4a, 4b and so forth, the second support 2 carries line electrodes 5a, 5b and so forth at its upper half facing the first support 1. The second support 2 is further provided with column electrodes 6a, 6b and so forth opposite the third support 3. The third support 3 carries line electrodes 7a, 7b and so forth at its lower half. Therefore, it is possible to make such a multi-layered panel by stacking the glass supports in this manner.
Moreover, with the multi-layered panel it is possible to increase the number of actual lines 2, 2.sup.2, etc. times while increasing the number of the column electrodes, 2, 2.sup.2 times, etc. This results in a remarkable increase in the terminal electrodes and difficulty in connecting the terminal electrodes through the use of commercially available connectors, electrode pins, etc., especially because of a stepped terminal structure of the multi-layered panel.
The conventional terminal assembly is now discussed with reference to FIG. 3 illustrating a perspective view of a two-layered structure liquid crystal panel. When matrix displaying is desired through the use of this panel, the column electrodes 4a, 4b and so forth of the first layer overlap with those 6a, 6b and so forth of the second layer as shown in FIG. 4 wherein picture elements 8 are ones appearing on the first layer and picture elements 9 are ones appearing on the second layer. Terminal electrodes are led from the respective column electrodes and especially the terminal electrodes 10a, 10b and so forth of the first layer overlap with those 11a and 11b of the second layer. With the above stepped terminal assembly, a wiring film 13 and 14 as shown in FIG. 5 is needed for each of the respective layers and a great difficulty is faced in drastically decreasing the distance L between connection pads P.sub.1 and P.sub.2 on circuit boards to which the two wiring films 13 and 14 are respectively connected. To this end the problem remains outstanding that the liquid crystal panel including its drive circuit is bulky and voluminous.